Community Forums

smithd7 · 05-03-2018, 09:57 PM

I have a ‘93 Fleetwood Flair 28 foot on a P32 Workhorse chassis with the 454 engine. I’m trying to see if my A/C will work. I’ve only had this motorhome a little over a year. There is no personal information packet and no info. for anything. I am trying to fine the fuse for the A/C system, I found the fuse block behind the instrument panel and can’t fine the one for the A/C.
Anyone have an idea just where that fuse might be?

I might add my question is regarding the engine compartment A/C.

jeeepz · 05-03-2018, 10:06 PM

Doees the blower fan work? Does the compressor cycle on and off? If the system is low on Freon the compressor stays off due to a low pressure cut out switch.

smithd7 · 05-04-2018, 08:54 AM

The blower fan is the same as the heater fan and yes it works. The compressor does not cycle at all there is no juice to it. The system is charged I just don’t know how much. Where is the cut out switch, can I bypass or disconnect it to check for power? Is there a main fuse for the A/C system?

wa8yxm · 05-04-2018, 05:29 PM

Depending on the compressor there may be some additional switches in line

A LOW PRESSURE switch, designed to keep the compressor from kicking in if there is no refrigeritant

A High Pressure Switch IF there is too much or if the expansion valve is .. Clogged.

And perhaps an anti-freeze switch (Thermostat)

ALso wires hook all this stuff up.. I had a broken wire.

CJ7365 · 05-04-2018, 05:44 PM

Quote:

Originally Posted by smithd7

The blower fan is the same as the heater fan and yes it works. The compressor does not cycle at all there is no juice to it. The system is charged I just don’t know how much. Where is the cut out switch, can I bypass or disconnect it to check for power? Is there a main fuse for the A/C system?

You have a 93, so it came with R12 refrigerant, is there a sticker anywhere that says its been replaced with 134a?

If not, it will be expensive to get it charged up with R12.

You could also look at the low and high pressure ports and see if there is a 134a adapter on them, if so then its probably been converted to 134a.

Yes you can bypass (override) the low pressure switch. But WAIT, you say you don't know how much refrigerant is in the system. You need a set of gauges, once you get the gauges you can see if you are low on refrigerant or you have a block (high pressure)

smithd7 · 05-04-2018, 08:34 PM

Quote:

Originally Posted by CJ7365

You have a 93, so it came with R12 refrigerant, is there a sticker anywhere that says its been replaced with 134a?

If not, it will be expensive to get it charged up with R12.

You could also look at the low and high pressure ports and see if there is a 134a adapter on them, if so then its probably been converted to 134a.

Yes you can bypass (override) the low pressure switch. But WAIT, you say you don't know how much refrigerant is in the system. You need a set of gauges, once you get the gauges you can see if you are low on refrigerant or you have a block (high pressure)

Yes the system is R12 I tried to hook up a 134a gauge to the low pressure side and it wouldn’t work. Would there be any power anywhere in the system I could check if the low pressure switch is activated?

ScottyBye · 05-24-2018, 11:20 PM

Your low pressure switch will be connected to the suction line of the compressor. It will have 2 wires. If you disconnect the wires and measure continuity through the switch it is closed. It will be wired in series with other safety switches in the system. If either of those switches open this will prevent your compressor from starting.
Have you checked the 110 volt breaker to make sure it is turned on and not tripped? Have you also checked to make sure you have a call for cooling from your thermostat?

ScottyBye · 05-24-2018, 11:28 PM

Quote:

Originally Posted by wa8yxm

A High Pressure Switch IF there is too much or if the expansion valve is .. Clogged.

The high pressure switch would not come into play if the expansion valve/metering device was clogged/closed as this would stop the flow of refrigerant into the evaporator. The compressor would still keep pumping until it either tripped on the LPC or thermal OL. And in order for the HPC to open the system would have to be grossly overcharged with refrigerant or possibly a faulty condenser fan(s) or dirty condenser. Even bent fins causing low air flow through the condenser.

wa8yxm · 05-25-2018, 06:51 AM

The high pressure switch will also respond to an over charge.

Something hinted at but I did not see expressly stated above

The fuse for the blower is also the fuse for the compressor. So if the blower blows. the fuse is good.

smithd7 · 05-28-2018, 09:18 PM

Quote:

Originally Posted by wa8yxm

The high pressure switch will also respond to an over charge.

Something hinted at but I did not see expressly stated above

The fuse for the blower is also the fuse for the compressor. So if the blower blows. the fuse is good.

The AC system I’m referring to is the engine bay and not the roof top unit.
When you say blower it is the same one used for the heater system.
Also the AC power system panel shows all breakers in the on position.
Will jump low pressure switch to see if that has any effect.

Thanks for all replies

ScottyBye · 05-28-2018, 09:27 PM

Quote:

Originally Posted by smithd7

Will jump low pressure switch to see if that has any effect.

I you are confident that there is refrigerant in the system then temporarily jumpering the LPC switch is ok but a better safer option might be to either measure voltage through the switch or remove it from the circuit and ohm the switch.